<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style type="text/css">
#head1{height:200px; background:green;}
#box{height:100px; background:#333;}
#wrap{height:20px; background:tan;}

.box{width:100px;height:100px; border:1px solid #333;}

</style>

</head>

<body>
css:层叠样式表，cascading  style sheets
html:超文本标记语言，hyper text markup language
<div id="head1"></div>
<div id="box"></div>
<div id="wrap"></div>
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
</body>
</html>
